Three point hitches are used by a variety of work vehicles, such as wheeled and tracked tractors, to attach an implement to the work vehicle and to raise or lower the implement relative to the work vehicle. Three point hitches generally include two spaced lower links and an upper link above and between the two lower links. Each of the upper link and lower links has an end configured for engaging and attaching the implement to the work vehicle. To lift the implement, the three point hitch generally includes one or more hydraulic cylinders, which directly or indirectly pivot the lower links to lower and raise the implement. As the implement is raised and lowered, the upper link stabilizes the implement and maintains the implement in a desired orientation relative to the work vehicle.
Three point hitches are generally either rear or front mounted. With rear-mounted three point hitches, the implement is secured to the vehicle at the rear of the vehicle and is pulled by the vehicle. In contrast, with front-mounted three point hitches, the implement is secured at the front end of the vehicle and is pushed by the vehicle. In many circumstances, work vehicles are provided with both rear and front-mounted three point hitches to simultaneously carry and utilize both front and rear implements.
Although similar to rear-mounted three point hitches, conventionally known front-mounted three point hitches have several unique operating characteristics and disadvantages because the three point hitch extends in front of the work vehicle. First, front-mounted three point hitches increase the length of the work vehicle. With conventional front-mounted three point hitches, the upper hitch link is pivotably supported about an axis at or forward the front of the work vehicle. Because the attachment point of the upper hitch link extends forward the front of the vehicle, the upper hitch link substantially increases the distance separating the operator from the forward most point of the work vehicle. As a result, the operator is also separated by a greater distance from a road intersection where visibility may be critical. In addition, the operator's general visibility may also be impaired due to perspective. For these reasons, many governmental bodies have enacted laws and regulations setting limits for the maximum distance that the operator may be separated or spaced from the forward most point of the work vehicle. For example, Europe includes regulations limiting the distance separating the forward most point of the vehicle and the front of the steering wheel to 3.5 meters. Larger work vehicles currently provided with front-mounted three point hitches or after market front-mounted three point hitches do not presently meet these regulations.
Second, because the front-mounted three point hitches are mounted at the front of the vehicle near the front axle, the implement carried by the three point hitch moves laterally as the work vehicle is being turned. Because the upper hitch link extends significantly forward the front of the work vehicle and significantly forward the front axle of the work vehicle, turning the work vehicle results in even larger lateral movements of the carried implement. Such large lateral movement is extremely undesirable when the implement being carried is in engagement with the ground.
Third, because the upper hitch link significantly extends forward the front of the work vehicle and forward the front axle, the mass of the implement carried by the hitch is even farther spaced from the front of the vehicle. As a result, larger loads are transmitted to the work vehicle. These larger loads reduce vehicle stability during both transport and field operation. Because the work vehicle must be designed to accommodate these larger loads, the manufacturing cost of the work vehicle is increased.
Thus, there is a continuing need for a front-mounted three point hitch which extends from the front of the work vehicle by a shorter distance to (1) reduce the distance separating the operator and the forward most point of the vehicle; (2) to enable larger work vehicles to meet governmental regulations limiting the maximum distance separating the forward most point of the work vehicle and steering wheel; (3) To reduce lateral movement of the three point hitch and the carried implement during turning of the work vehicle and (4) to couple the mass of the carried implement closer to the work vehicle to reduce manufacturing costs for the work vehicle.